Example

Solving a Uniform Motion Application: Biking Speed with Equal Travel Times

Apply the distance, rate, and time problem-solving strategy to find an unknown vehicle speed when different distances are covered in equal time—one segment with a headwind and one with a tailwind.

Problem: Link has an electric bike which runs at a constant speed. He can ride his bike 2020 miles into a 33 mph headwind in the same amount of time he can ride 3030 miles with a 33 mph tailwind. What is Link’s biking speed?

  1. Read and draw: Sketch two paths — one for 2020 miles against the wind and one for 3030 miles with the wind. Create a rate–time–distance table.
  2. Identify: Link's biking speed in still air.
  3. Name: Let rr = Link's biking speed. The headwind rate is r3r - 3; the tailwind rate is r+3r + 3. Because t=Drt = \frac{D}{r}, the times are 20r3\frac{20}{r - 3} and 30r+3\frac{30}{r + 3}.
  4. Translate: The travel times are equal: 20r3=30r+3\frac{20}{r - 3} = \frac{30}{r + 3}
  5. Solve: Multiply both sides by the LCD, (r3)(r+3)(r - 3)(r + 3): 20(r+3)=30(r3)20(r + 3) = 30(r - 3) 20r+60=30r9020r + 60 = 30r - 90 150=10r150 = 10r r=15r = 15
  6. Check: Headwind time: 20153=2012=53\frac{20}{15 - 3} = \frac{20}{12} = \frac{5}{3} hours. Tailwind time: 3015+3=3018=53\frac{30}{15 + 3} = \frac{30}{18} = \frac{5}{3} hours. The times are equal. \checkmark
  7. Answer: Link's biking speed is 1515 mph.

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Updated 2026-05-01

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